modeling optical fiber using matlab

[mohammed hosni]

please i need to design WDM communication system by using PMMA polymer fiber with the following parameter attenuation 150 db/km , length 20 m,temperature 70 Celsius,core size 980 micro meter , cladding size 1mm.
as there isn’t PMMA polymer fiber component in optisystem so i need to model PMMA polymer fiber with the mentioned parameter using matlab component. if there is another way to use optical fiber component in optisystem please tell me it if not please tell me how i can model first glass optical fiber using matlab component to compare the results with the optical fiber component which already exist in optisystem software .
then i will model PMMA polymer fiber.
i need your help for my master degree study.
thanks.

[Damian Marek]

If you have more information about the fiber you can do it directly in OptiSystem, like core refractive index, cladding index etc.

[mohammed hosni]

what about the other mentioned parameters?
what about modeling optical fiber with matlab component?

[Abdallah Ismail]

We are modeling fiber using split step Fourier method that solve Schrodinger equation.
In case that your fiber is a special case of SMF or MMF, you can use Measured components of theses fibers with your parameters that Damian mentioned above to model your fiber.

[Dr Rk Sethi]

Abdallah Hi,
Can you elaborate, how are you modelling and simulating fiber.
thanks and regards,
Sethi Rk

[mohammed hosni]

Refractive index=1.4906
Chromatic dispersion=dn/dλ = -0.043329 µm-1
Group velocity dispersion
GVD = 81.808 fs2/mm
D = -446.31 ps/(nm km)
Dispersion formula
n2−1=0.99654λ2λ2−0.00787+0.18964λ2λ2−0.02191+0.00411λ2λ2−3.85727

[Abdallah Ismail]

Is this dispersion value is real?

[mohammed hosni]

yes

[mohammed hosni]

please find the attached files matlam m.file for modeling the attenuation and the dispersion of fibe that is just example but there is an error about the dispersion please help me to model the dispersion by matlab

[mohammed hosni]

that is optisystem file

[Abdallah Ismail]

I hope the attached files, helps you Mohamed.

[Abdallah Ismail]

There is a problem with the attachments

Attachments:

1. fiber_run.m

[Abdallah Ismail]

also this one

[Abdallah Ismail]

that is it

[Abdallah Ismail]

hope optiwave solve it

[mohammed hosni]

thanks Abdallah Ismail
but how can i use this file with optisystem matlab component

[Abdallah Ismail]

it’ll not work without the function

[Abdallah Ismail]

hope it attached for the last time

[Abdallah Ismail]

copy this code to a function file with name sym_ssf
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%55
function [to,fo] = sym_ssf(M,h,gamma,Dh,uf0)
% Symmetrized Split-Step Fourier Algorithm
%
% ==Inputs==
% M = Simulation step number ( M*h = simulation distance )
% h = Simulation step
% gamma = Nonlinearity coefficient
% Dh = Dispersion operator in frequency domain
% uf0 = Input field in the frequency domain
%
% ==Outputs==
% to = Output field in the time domain
% fo = Output field in the frequency domain
%
% written by Jong-Hyung Lee
for k = 1:M
%=============================================================
% Propagation in the first half dispersion region, z to z+h/2
%=============================================================
Hf = Dh.*uf0;
%==========================================================
% Initial estimate of the nonlinear phase shift at z+(h/2)
%==========================================================
% Initial estimate value
ht = ifft(Hf); % time signal after h/2 dispersion region
pq = ht.*conj(ht); % intensity in time
u2e = ht.*exp(h*1i*gamma*pq); %Time signal
%=============================================================
% Propagation in the second Dispersion Region, z+(h/2) to z+h
%=============================================================
u2ef = fft(u2e);
u3ef = u2ef.*Dh;
u3e = ifft(u3ef);
u3ei = u3e.*conj(u3e);
%========================================================
% Iteration for the nonlinear phase shift(two iterations)
%========================================================
u2 = ht.*exp((h/2)*1i*gamma*(pq+u3ei));
u2f = fft(u2) ;
u3f = u2f.* Dh;
u4 = ifft(u3f);
u4i = u4.*conj(u4);
u5 = ht.*exp((h/2)*1i*gamma*(pq+u4i));
u5f = fft(u5);
uf0 = u5f.*Dh;
u6 = ifft(uf0); u6i = u6.*conj(u6);
%=============================================================
% Maximum allowable tolerance after the two iterations
etol = 1e-5;
if abs(max(abs(u6i))-max(abs(u4i)))/max(abs(u6i)) > etol
disp(‘Peak value is not converging Reduce Step Size’),break
end
%=============================================================
end
to = u6; fo = uf0;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

[Abdallah Ismail]

I think that code will not help you, where your fiber can not be modeled with SMF Schrodinger’s equation.
Schrodinger’s equation is not used for modeling multimode fiber as well as PMMA polymer fiber.
There are conditions for Schrodinger’s equation to be valid.
Try to look for modeling PMMA polymer fiber, and i think you can use another tools of optiwave for this purpose.
Regards,

[mohammed hosni]

if i want this code for smf fiber how can i use this code with optisytem matlab component

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